Pressure compensation valve

Abstract

A pressure compensation valve has a check valve portion with a check valve bore with an inlet port and an outlet port in a valve body, a valve in the check valve bore for establishing and blocking communication between the inlet port and the outlet port, a pressure reduction valve portion constructed by forming a pressure reducing valve bore having a first port, a second port and a third port and being coaxial with the check valve bore in the valve body, a spring-biased spool in the pressure reduction valve bore to define a first pressure chamber communicating with the first port and a second pressure chamber communicating with the third port at both sides, making the second port communicate with the third port by a pressure of the first pressure chamber, and blocking communication between the second port and the third port by the pressure in the second pressure chamber.

We claim: 
     
       1. A pressure compensation valve comprising: a check valve portion constructed by forming a check valve bore with an inlet port and an outlet port in a valve body, and slidably disposing a valve in said check valve bore for establishing and blocking communication between said inlet port and said outlet port;   a pressure reduction valve portion constructed by forming a pressure reducing valve bore having a first port, a second port and a third port and being coaxial with said check valve bore in said valve body, slidably disposing a spool in said pressure reduction valve bore to define a first pressure chamber communicating with said first port and a second pressure chamber communicating with said third port at both sides, making said second port communicate with said third port by a pressure of said first pressure chamber, and blocking communication between said second port and said third port by the pressure in said second pressure chamber;   said spool being pushed in a direction for blocking communication between said second port and said third port by a spring to cause pressure contact with said valve to push said valve in a valve closing direction,   wherein said pressure receiving valve further comprising:   a pressure receiving chamber communicating with said second port via an orifice and pushing said spool in a direction for blocking communication by the pressure therein;   a fluid passage for establishing communication between said pressure receiving chamber and said outlet port when said valve is in a communicating position, and   pressure adjusting means for adjustably setting a pressure in said pressure receiving chamber.   
     
     
       2. A pressure compensation valve as set forth in claim 1, wherein said pressure adjusting means is constructed with a fixed path area orifice provided at an upstream side of said fluid passage and a variable relief valve provided at a downstream side. 
     
     
       3. A pressure compensation valve as set forth in claim 1, wherein said pressure adjusting means is a variable orifice.